Various amino acids, their analogues and vitamins have shown stimulatory as well as inhibitory effects on laccase production by Cyathus bulleri. (DL)-methionine, (DL)-tryptophan, glycine and (DL)-valine stimulated laccase production, while L-cysteine monohydrochloride completely inhibited the enzyme production. Among vitamins tested biotin, riboflavin and pyridoxine hydrochloride were found to induce laccase production.